1. Field of the invention
In general, the present invention relates to the monitoring and analyzing of media quality and drive hardware performance of a media library comprising a plurality of removable storage media, a plurality of drive units for said storage media and means for moving said storage media to and from appropriate drive units,
wherein said media library is managed by a management system being connected to said media library.
2. Description of the Related Art
Tape drive technology comprising a Statistical Analysis and Reporting System (SARS) is well known in the prior art. Examples of such include International Business Machines' IBM Total Storage™ 3590 tape drive, IBM LTO and IBM Total Storage™ 3592 tape drive. SARS is part of the tape drive firmware and provides Media and Hardware algorithms for monitoring and analyzing media and hardware failures during every load, data transfer and unload cycle. Thereby, statistical and error information is recorded for every tape operation and serves as historical information for drive hardware and media analysis. SARS analyzes tape drive and tape cartridge performance as well, to determine:
1) Whether the tape cartridge or the hardware in the tape drive is causing unreported errors.
2) If the tape media is degrading over time.
3) If the tape drive hardware is degrading over time.
As a result of this analysis SARS provides messages according to the SCSI standard such as media information messages (MIM), system information messages (SIM) or tape alerts. The historical information and analysis results are stored in a non-volatile memory within the drive and in parallel in the tape cartridge memory chip (LTO, 3592) using a non-contact, low-level radio frequency (RF) field, generated by the drive. Alternatively, this information is stored in a VCR (Volume Control Region) for IBM 3590 technology. If a tape drive performs poorly with different tape volumes, a self-diagnostic test is performed and service repair messages or error codes are presented via the operator panel, StorWatch, SNMP and/or call home functions. Similarly, if individual tape volumes show poor performance on different drives, ‘read-only’ or ‘discard-media’ messages are presented. So SARS is already a good base to analyze hardware and media errors and determine trends.
In some cases it is difficult for the SARS algorithm to differentiate between media and drive hardware errors. This is because SARS runs usually separately on every tape drive and therefore a given tape drive's SARS algorithm has no notion how a particular media performs in other drives or how other drives perform. But this information might be needed in order to differentiate between drive hardware and media errors. This lack causes higher replacement rates, higher service cost and customer dissatisfaction.
Some examples for errors which might not be clearly differentiated and related to either the media or the drive hardware are:                a) Damaged edges on media—where the edge of the media is wrinkled for example. In these cases the SARS method cannot clearly identify the failure because it does not know whether the read-write heads near the edge are performing bad or whether the edge of the tape is damaged.        b) Vertical or horizontal scratches on the media        c) Detection of media folds        d) Coating issues of the media which can vary from different media vendors production technology        e) Certain scenarios of head defects where the SARS method might not be able to differentiate between media or R/W head related errors, especially if the R/W head performance is marginal        f) “bearing flutter” of tape path rollers (quality issue) which downgrades performance and number of (backward) datasets written on a tape.        
These errors could be clearly differentiated if a media of a known quality is used for error isolation and compared against the performance of the media or drive in question.
In summary, SARS automatically analyzes the performance and error statistic for a given tape drive and storage medium. SARS has some limitations when it comes to errors which cannot be clearly identified as either media errors or drive hardware errors. This limitation is mainly because SARS does not compare a “good” media to a “bad” media or a “good” R/W head to a “bad” R/W head.
There is a need to enhance the prior art techniques of monitoring and analysing the media quality and drive hardware performance of a media library.